fast_levenshtein_distance.js

function getLevenshteinDistance(a, b) {
	var tmp;
	if (a.length === 0) { return b.length; }
	if (b.length === 0) { return a.length; }
	if (a.length > b.length) { tmp = a; a = b; b = tmp; }

	var i, j, res, alen = a.length, blen = b.length, row = Array(alen);
	for (i = 0; i <= alen; i++) { row[i] = i; }

	for (i = 1; i <= blen; i++) {
		res = i;
		for (j = 1; j <= alen; j++) {
			tmp = row[j - 1];
			row[j - 1] = res;
			res = b[i - 1] === a[j - 1] ? tmp : Math.min(tmp + 1, Math.min(res + 1, row[j] + 1));
		}
	}
	return res;
}


/*Returns a percentage indicating how close the strings matched. Is included because jsPerf doesn't let you remove cases...*/
function findMatchPercent(a, b) {
	var tmp;
	if (a.length === 0) { return b.length; }
	if (b.length === 0) { return a.length; }
	if (a.length > b.length) { tmp = a; a = b; b = tmp; }

	var i, j, res, alen = a.length, blen = b.length, row = Array(alen);
	for (i = 0; i <= alen; i++) { row[i] = i; }

	for (i = 1; i <= blen; i++) {
		res = i;
		for (j = 1; j <= alen; j++) {
			tmp = row[j - 1];
			row[j - 1] = res;
			res = b[i - 1] === a[j - 1] ? tmp : Math.min(tmp + 1, Math.min(res + 1, row[j] + 1));
		}
	}
	return (blen - res) / blen;
}

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